乙醇对斜生栅藻叶绿素荧光特性以及油脂积累的影响研究

为了研究乙醇对斜生栅藻(Scenedesmus obliquus XJ002)藻株光合效率以及胞内油脂积累的影响,首先采用酶标仪作为检测仪器,研究了尼罗红终浓度、二甲基亚砜(DMSO)体积分数、尼罗红染色时间对藻株油脂测定的影响,分析了藻株胞内油脂含量与尼罗红染色相对荧光信号强度之间的线性关系,为XJ002藻株胞内油脂含量的测定提供了一个简便、快速的方法.其次研究了不同体积分数的乙醇添加对XJ002藻株生物量、叶绿素荧光特性以及胞内总脂含量的影响.结果表明:XJ002藻细胞尼罗红染色最佳条件是:二甲基亚砜体积分数为2%,尼罗红的终质量浓度为2.0μg·m L~(-1),尼罗红的染色时间为5 min.添加高浓度乙醇导致藻细胞生物量与光合色素含量显著下降,影响了藻细胞光系统Ⅱ反应中心能量分配,抑制光系统Ⅱ反应中心受体侧电子传递活性.当乙醇处理浓度为3%时,XJ002藻株胞内总脂含量较对照组提高了5.19%,该研究表明乙醇可以作为XJ002藻株油脂积累的潜在诱导试剂.     

外源一氧化氮调控三角褐指藻响应氮胁迫的作用研究

为探究外源一氧化氮(Nitric Oxide, NO)对三角褐指藻(Phaeodactylum tricornutum)响应氮胁迫的作用,本研究通过添加外源NO供体硝普钠(Sodium Nitroprusside, SNP)及NO清除剂[2-(4-carboxyphenyl)-4,4,5,5-teramethylimidazoline-1-oxyl-3-oxide, cPTIO],探讨外源NO对氮胁迫条件下的三角褐指藻细胞密度、叶绿素含量、叶绿素荧光参数、岩藻黄素含量、油脂相对含量等的影响。结果表明,缺氮会抑制三角褐指藻细胞的生长,显著降低叶绿素a (chla)含量与光合效率,降低岩藻黄素含量,增加脂质合成。与氮正常情况下相比,在缺氮条件下添加200μmol/L SNP可在一定程度上缓解缺氮对三角褐指藻生长、叶绿素含量、光合效率与岩藻黄素积累的抑制,并能显著促进油脂的积累。在缺氮条件下添加50μmol/L cPTIO对三角褐指藻的生长、叶绿素含量、光合效率及物质积累影响不大。本研究可为探明外源NO调控三角褐指藻响应氮胁迫的作用机制提供基础数据,也为进一步提高逆境条件下三角褐指藻的生物量...     

二酰基甘油转移酶对三角褐指藻油脂积累及相关环境因子响应的研究

本文应用RT-PCR和RACE方法扩增出三角褐指藻二酰基甘油转移酶(Ptdgat)全长cDNA,其完整编码框(ORF)为1587 bp,编码528个氨基酸.基于克隆所得Ptdgat的ORF构建了反向互补RNA干扰载体,并用基因枪PDS-1000/He转化野生型三角褐指藻,筛选到了所需的阳性转基因藻.实时荧光定量PCR(qPCR)结果揭示:含Ptdgat RNA干扰结构的转基因藻的二酰基甘油转移酶的表达水平比野生型三角褐指藻该酶的表达水平有显著降低;野生型藻和转基因藻的油脂含量定量分析结果揭示:含RNAi干扰结构的转基因三角褐指藻油脂含量也明显低于野生型三角褐指藻.另外本文也揭示了适当浓度的外源培养因子铁、硅和脱落酸(ABA)提高了三角褐指藻Ptdgat基因的表达水平及其油脂含量.     

过表达甘油激酶三角褐指藻藻株富集油脂的研究

为了得到高产并符合生物柴油标准的微藻油脂的藻株,本文研究了在外源甘油存在的情况下野生型（WT）三角褐指藻（Phaeodactylum tricornutum）,甘油激酶过表达藻株（GKOE）以及甘油激酶RNA干扰藻株（GKRNi）在添加浓度为20 mmol/L外源甘油的培养基中的生长情况、油脂产量以及脂肪酸组成.结果显示：（1）甘油兼养的GKOE藻细胞浓度可达到2.23×107个/mL,明显高于甘油兼养的WT的1.79×107个/mL和GKRNi的1.78×107 个/mL;（2）甘油兼养的GKOE油脂含量可达到31.73%,比甘油兼养的WT和GKRNi分别高了27.20%和26.63%;（3）尼罗红染色显示甘油兼养的GKOE荧光强度比甘油兼养的WT和GKRNi分别高16.26%和17.83%;（4）甘油兼养的GKOE总脂肪酸产量可达到0.052 mg/mL,比甘油兼养的WT和GKRNi高了36.84%和10.64%,说明其油脂适合于生物柴油开发.     

制浆造纸废水曝露对藻类的毒性效应

以AOX含量为17.87 mg/L,CODCr含量为707.0 mg/L的化学制浆造纸漂白废水为实验液,开展其对三角褐指藻和扁藻的96 h毒性效应实验。结果表明:实验用造纸废水对三角褐指藻和扁藻的96 h-EC₅₀AOX浓度介于2.91².87 mg/L,COD_Cr浓度介于176.3¹38.7 mg/L。与同等稀释条件下鱼类、虾蟹类和贝类的实验相比,藻类的敏感性较高。     

三角褐指藻(Phaeodactylum tricornutm) 油脂富集培养的研究

探讨了营养盐铁、硅及植物激素脱落酸(ABA)单因子对三角褐指藻(Phaeodactylum tricornutum)的生长、油脂含量(%干重)及油脂产量的影响.采用光密度值OD450评价微藻的生长状况,以溶剂浸提法提取油脂.结果表明:(1)铁处理组中,铁浓度在0～46.57 μmol/L范围内时,藻的生长速率随铁浓度提高而增大;铁浓度为11.64 μmol/L时,油脂含量达30%,高于其它铁浓度培养;当铁浓度为11.64 μmol/L时,油脂产量最高--是无铁培养的2.8倍;(2)硅处理组中,低含量硅盐(4.6 μmol/L)不仅促进了藻的生长而且提高了油脂含量,油脂产量比高含量硅盐(42.6 μmol/L)培养提高了40%;(3)ABA处理组中,1 mg/L ABA不仅促进了藻的生长而且提高了油脂含量,油脂产量比对照提高了50%;5 mg/L ABA虽提高了油脂含量但却抑制了藻的生长,油脂产量和对照相当;15 mg/L ABA抑制了藻的生长、降低了油脂含量.用气相色谱分析微藻的脂肪酸组成,结果显示:1 mg/L ABA明显影响了三角褐指藻的脂肪酸组成,以高产量油脂(4.6 μmol/L硅盐、1 mg/L ABA培养)为原料制备出的生物柴油的质量将会提高.     

原油水溶性组分对2种微藻的毒性效应及微藻对石油烃的降解研究初探

为探索石油水溶性成分(WAF)对海洋微藻的毒性效应及海洋微藻对其的降解,研究了96 h内不同浓度WAF暴露下2种海洋微藻的细胞密度、生长率及抑制率,并在实验完成时测定微藻培养液中WAF的剩余量。实验结果表明低浓度的WAF能促进2种微藻的生长,当WAF浓度大于2.90 mg/L时,小球藻的生长受到抑制,当WAF浓度大于6.97 mg/L时,三角褐指藻的生长受到抑制,且呈现明显的剂量-时间效应。相对于小球藻,三角褐指藻对高浓度WAF的耐受性较强,受到的抑制较轻。96 h时,2种微藻培养液中的WAF浓度均有显著降低,但三角褐指藻实验组中WAF浓度降幅较大,其可能的原因是三角褐指藻对WAF的耐受性较强,藻细胞密度较高,从而对WAF有较高的降解效率,因此可用于降解含有WAF的污染海水。     

RNA干扰PEPC对三角褐指藻油脂含量的影响

本文应用生物信息学和RT-PCR方法分别获得了三角褐指藻两个PEPC全长cDNA,分别称为:PtPEPC1和PtPEPC2,前者完整开放阅读框3030bp,编码1009个氨基酸,后者完整开放阅读框2634bp,编码877个氨基酸;基于克隆所得PtPEPC的ORF构建了反向互补RNA干扰载体pPha-PtPEPC1RNAi和pPha-PtPEPC2RNAi,并用轰击法(PDS-1000/He)转化野生型三角褐指藻,筛选鉴定到了所需的阳性转基因藻;实时定量RT-PCR结果揭示:含PtPEPC RNA干扰结构的转基因藻的PEPCase基因的表达水平比野生型三角褐指藻该酶的表达水平有显著降低;野生型藻和转基因藻的油脂含量定量分析结果揭示:含RNAi干扰结构的转基因三角褐指藻油脂含量也明显高于野生型三角褐指藻,油脂增幅达2%~12%.     

氮源及其浓度对三角褐指藻生长及其脂肪酸组成的影响

为研究氮源的种类和浓度对三角褐指藻(Phaeodactylum tricornutum)生长及脂肪酸组成的影响,用含有不同浓度的NO-3和NH4 在叉培养基中对三角褐指藻进行培养,测定了其生长及脂肪酸的组成.结果表明,以NH4 为氮源时三角褐指藻的比生长速率大于硝酸钠;在NH 4为2.1 mmol/L时三角褐指藻达到最高比生长速率.三角褐指藻的主要脂肪酸是14: 0、16:0、16:1和20:5n-3(二十碳五烯酸,EPA).以NO-3为氮源时,EPA和高度不饱和脂肪酸(PUFAs)含量随着NO-3浓度增加先上升后下降,在1.0 mmol/L时的EPA占总脂肪酸质量分数比达到最高(16.9%).当氯化铵浓度大于3.9 mmol/L时,EPA的含量占总脂肪酸质量分数比随浓度的增加较大,在8.0mmol/L达到26.1%.     

猪粪废水用于三角褐指藻培养的研究

研究了以猪粪废水培养一株三角褐指藻(Phaeodactylum tricornutum)的可行性.结果表明:猪粪废水经30g/L盐水适当稀释后可直接用于三角褐指藻的培养,无需添加其他营养物质.在污水稀释率为25倍时,藻细胞可良好地生长,最高密度为合成培养基的1.52倍.同时三角褐指藻有效去除了污水中的氮磷,总氮、氨氮和总磷的去除率分别为23%,93%和93%.与合成培养基养殖的藻相比,猪粪废水养殖的三角褐指藻的二十碳五烯酸和多不饱和脂肪酸的含量略有上升,实现了培养三角褐指藻转化废水为生物量并积累多不饱和脂肪酸的资源化.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that